This application is based on Application No. 367124 filed in Japan on Nov. 30, 2001, the content of which is incorporated hereinto by reference.
This invention relates to a battery pack provided with authentication circuitry which can discriminate between genuine and imitation products.
A battery pack is attached to electrical equipment in a detachable manner to supply electric power to that equipment, or it is attached to a battery charger to be charged. Battery packs of various specifications are manufactured to correspond to electrical equipment parameters such as operating voltage and current. Battery pack characteristics such as output voltage and battery capacity are different for these different battery packs, and during battery charging, optimum charging current and charging time are set for each battery pack. Consequently, many different kinds of battery chargers have been developed to accommodate various battery packs. Attachment of a battery pack which does not meet battery charger or electrical equipment specifications invites charging problems such as over-charge or under-charge and electrical equipment malfunction. Use of an out-of-specification battery pack can be associated with electrical equipment or battery charger failure, and shortened battery pack life can be anticipated with repeated charging and discharging. Accordingly, a strategy is required to insure that only a battery pack meeting electrical equipment and battery charger specifications is attached.
Battery packs, developed to authenticate genuine versus imitation products, are roughly divided into two types. The first type is cited, for example, in Japanese Patent Application SHO 63-118132 (1988). For this type of battery pack, electrical equipment is provided with a region of projections and cavities on its battery attachment surface and authenticity is mechanically judged by shape. Battery pack attachment to electrical equipment is restricted to battery packs having a region of projections and cavities that fits with the electrical equipment. As a result, battery packs which meet electrical equipment specifications can be attached, and electrical equipment malfunction can be prevented.
However, discrimination of battery pack type by mechanical fit requires providing a region of projections and cavities on the electrical equipment and on the battery pack. This not only makes the shape of the battery pack exterior case complex, it has drawbacks such as making mass production unsuitable because different exterior cases are required corresponding to different types of battery packs. Further, it has the drawback that imitation battery packs with the same exterior shape as genuine battery packs cannot be discriminated. An inferior imitation battery pack with the same shape as a genuine battery pack may be returned to the manufacturer or service center as a defective product. It is then necessary to disassemble the imitation battery pack and confirm internal components to judge its authenticity, which costs time and money.
These drawbacks can be eliminated with a system, as cited in Japanese Patent Application HEI 5-198293 (1994), which electrically judges authenticity. A battery pack for electrically determining authenticity contains authenticity judging circuitry to communicate signals, such as identification (ID) signals, between electrical equipment and battery pack. Further, the battery pack is provided with a signal terminal to output authentication signals from the authenticity judging circuitry. When this battery pack is attached to electrical equipment or a battery charger, the signal terminal of the battery pack contacts a signal terminal provided on the electrical equipment or battery charger. Then battery pack authentication circuitry communicates signals with the electrical equipment or battery charger via mutually contacting signal terminals to determine authenticity. This battery pack sends and receives electrical signals via its signal terminal to allow determination whether the battery pack is proper or not.
However, since this battery pack""s authentication circuitry is driven by the battery pack rechargeable battery, it has the drawback that it consumes electrical power. Power consumed by the authentication circuitry can be the cause of over-discharge of the rechargeable battery housed in the battery pack. A battery pack may contain not only authentication circuitry, but also protection circuitry to prevent over-charge and over-discharge. When both protection circuitry and authentication circuitry consume electrical power, the detrimental effect of over-discharge can occur particularly easily. Since protection circuitry continually monitors the state of the battery, consumption of rechargeable battery power is unavoidable. However, since authentication circuitry determines whether or not the product is genuine only when the battery pack is attached, its operating time is extremely limited. As a result, it is necessary to reduce authentication circuitry power consumption as much as possible, but due to circuit structure there is a limit to this reduction, and it cannot be reduced to zero. Further, this battery pack sends and receives authentication signals to and from electrical equipment via signal terminals. It has the drawback that If contact failure occurs at the signal terminals, the battery pack cannot be used even if it is a normally usable battery pack.
The present invention was developed to resolve these types of drawbacks. Thus it is a primary object of the present invention to provide a battery pack containing authentication circuitry which can discriminate authenticity without consuming power from the rechargeable battery housed in the battery pack, and further which does not malfunction due to such causes as terminal contact failure or resistance. Another important object of the present invention is to provide a battery pack with authentication circuitry which is not restricted in its location inside the battery pack, and which can be simply, easily, and efficiently produced in quantity. The above and further objects and features of the invention will more fully be apparent from the following detailed description with accompanying drawings.
The battery pack of the present invention is provided with a rechargeable battery, output terminals connected directly to the rechargeable battery or via a switching device, and an authenticity discriminating circuit that outputs a specified signal to the connected electrical equipment to discriminate battery pack authenticity. Electrical power from the rechargeable battery is not supplied to the authenticity discriminating circuit. Further, this authenticity discriminating circuit is not connected to either the rechargeable battery or to the output terminals. The authenticity discriminating circuit is provided with a receiver section to receive an activating radio wave sent from the connected electrical equipment, a transmitter section to send an authentication radio wave which is the carrier modulated by a specified authentication signal issued when the receiver section receives the activating radio wave, and a power supply section to convert the activating radio wave sent from the electrical equipment to direct current (DC) to supply power to the receiver section and transmitter section. The authenticity discriminating circuit receives the activating radio wave sent from the electrical equipment when the battery pack is attached, the power supply section supplies power to the receiver section and transmitter section, and the transmitter section sends the authentication radio wave to determine authenticity. (Note, the general term radio wave designates a wireless electromagnetic transmission and is not meant to specify or limit in any way the frequency band of those transmitted waves.)
This configuration of battery pack has the characteristic that authenticity can be discriminated without consuming power from the rechargeable battery housed in the battery pack. This is because the battery pack contains an authenticity discriminating circuit which outputs the battery pack""s authentication signal to the connected electrical equipment, and this authenticity discriminating circuit is provided with a receiver section to receive the activating radio wave sent from the electrical equipment, a transmitter section to send the authentication radio wave when the receiver section receives the activating radio wave, and a power supply section to convert the activating radio wave sent from the electrical equipment to DC to supply power to the receiver and transmitter sections.
This configuration of battery pack does not supply electrical power to the authenticity discriminating circuit from its internal rechargeable battery, but rather the activating radio wave sent from the electrical equipment is converted to DC power and supplied to the receiver and transmitter sections. Therefore, internal rechargeable battery power is not consumed. As a result, rechargeable battery over-discharge due to authenticity discriminating circuit power consumption is reliably prevented. Further, since this authenticity discriminating circuit trades signals with the electrical equipment by sending and receiving radio waves, and is not connected to the rechargeable battery or to the output terminals, malfunction due to terminal contact failure or resistance can be eliminated. Still further, since the authenticity discriminating circuit of this battery pack does not require any wiring, the circuit can be located anywhere in the battery pack without restriction. Therefore, this battery pack has the characteristic that it can be simply, easily, efficiently, and inexpensively manufactured in quantity.
Finally, since genuine and imitation battery pack authenticity is discriminated by sending and receiving specified radio waves, even battery packs with the same exterior shape can be easily and reliably judged as genuine or imitation without disassembly. Therefore, the waste of time and resources discriminating between genuine and imitation products is minimized, and failures which are poor imitations are effectively excluded.